Refractory vessels and methods for forming same

Abstract

The disclosure relates to methods of forming a vessel and to the resulting vessel. The vessel may be formed by providing a first fumed silica soot layer comprised of primary particles of fumed silica soot, and then providing over the first fumed silica soot layer a second fumed silica soot layer comprised of agglomerated particles formed into an agglomerated form from primary particles of fumed silica soot. The primary particles of the first fumed silica soot layer may have a substantially uniform density distribution, and the agglomerated particles of the second fumed silica soot layer may have a substantially non-uniform density distribution. The methods may include consolidating the first and second soot layers together to form a consolidated body.

What is claimed is: 
     
       1. A method of forming a vessel, the method comprising:
 providing a first fumed silica soot layer comprised of primary particles of fumed silica soot, 
 providing over the first fumed silica soot layer a second fumed silica soot layer comprised of agglomerated particles formed from primary particles of fumed silica soot, and 
 compacting the first and second soot layers together to form a vessel, wherein 
 the primary particles of the first fumed silica soot layer have a substantially uniform density distribution, and the agglomerated particles of the second fumed silica soot layer have a substantially non-uniform density distribution. 
 
     
     
       2. The method according to  claim 1 , further comprising cleaning the first and second layers of fumed silica soot prior to the step of compacting the layers. 
     
     
       3. The method according to  claim 1 , wherein the agglomerated particles are at least about 5 microns in diameter. 
     
     
       4. The method according to  claim 1 , wherein the primary particles are about 0.25 microns or less in diameter. 
     
     
       5. The method according to  claim 1 , wherein an average surface area of the first fumed silica soot layer ranges from about 10 m 2 /g to about 100 m 2 /g. 
     
     
       6. The method according to  claim 1 , wherein the second fumed silica soot layer is modified by a process that increases an initial tap density ranging from about 0.1 g/cm 3  to about 0.4 g/cm 3  of the fumed silica soot of the second layer, to a modified tap density ranging from about 0.35 g/cm 3  to about 0.9 g/cm 3  in order to form the agglomerated particles. 
     
     
       7. The method according to  claim 1 , wherein the agglomerated particles of the second fumed silica soot layer are formed from the primary particles of fumed silica soot by rolling the fumed silica soot. 
     
     
       8. The method according to  claim 1 , wherein the agglomerated particles of the second fumed silica soot layer are formed from the primary particles of fumed silica soot by vibramilling or shaking/mixing the fumed silica soot. 
     
     
       9. The method according to  claim 1 , wherein the agglomerated particles of the second fumed silica soot layer are formed from the primary particles by dispersing the fumed silica soot in water and spray-drying the dispersed fumed silica soot. 
     
     
       10. A method of forming a vessel, the method comprising:
 providing a first fumed silica soot layer comprised of primary particles of fumed silica soot, wherein the primary particles of the first fumed silica soot layer have a substantially uniform density distribution; 
 compacting the first fumed silica soot layer; 
 modifying fumed silica soot by a process to form a second fumed silica soot layer comprised of agglomerated particles from primary particles of fumed silica soot, wherein the agglomerated particles of the second fumed silica soot layer have a substantially non-uniform density distribution; 
 compacting the second fumed silica soot layer, the first fumed silica soot layer and the second fumed silica soot layer being compacted together into a compacted structure; and 
 consolidating the first and second fumed silica soot layers together to form a vessel. 
 
     
     
       11. The method according to  claim 10 , wherein compacting the first fumed silica soot layer further comprises:
 providing the first fumed silica soot layer within a first pressing mold about a well mold disposed within the first pressing mold, and 
 compacting the first fumed silica soot layer about the well mold to form a vessel well. 
 
     
     
       12. The method according to  claim 11 , wherein compacting the first fumed silica soot layer further comprises pre-compacting a portion of the fumed silica soot of the first soot layer between the well mold and the first pressing mold. 
     
     
       13. The method according to  claim 10 , wherein compacting the second fumed silica soot layer further comprises providing the compacted first fumed silica soot layer within a second pressing mold, providing the second fumed silica soot layer over the compacted first fumed silica soot layer and compacting the second fumed silica soot layer. 
     
     
       14. The method according to  claim 13 , wherein first fumed silica soot layer and the second fumed silica soot layer are compacted in an axial direction with respect to a central axis of the first pressing mold and a central axis of the second pressing mold. 
     
     
       15. The method according to  claim 13 , wherein the first fumed silica soot layer and the second fumed silica soot layer are compacted in a radial direction with respect to a central axis of the first pressing mold and a central axis of the second pressing mold. 
     
     
       16. The method according to  claim 10 , wherein the first fumed silica soot layer and the second fumed silica soot layer are compacted together in a single compaction. 
     
     
       17. The method according to  claim 10 , wherein the first fumed silica soot layer is compacted from an initial tap density of from about 0.1 g/cm 3  to 0.4 g/cm 3  to a pressed density of from about 0.6 g/cm 3  to 1.2 g/cm 3 . 
     
     
       18. The method according to  claim 10 , wherein the second fumed silica soot layer is compacted from a modified tap density of from about 0.35 g/cm 3  to 0.9 g/cm 3  to a pressed density of from about 0.6 g/cm 3  to 1.2 g/cm 3 . 
     
     
       19. The method according to  claim 10 , wherein compacting the second fumed silica soot layer forms interstitial void spaces between the agglomerate particles ranging from about 1 micron to 100 microns. 
     
     
       20. The method according to  claim 10 , wherein consolidating the first and second soot layers together further comprises heating the first fumed silica soot layer and the second fumed silica soot layer to densify the first fumed silica soot layer and second fumed silica soot layer.